Properties and Applications of 1.4742 Stainless Steel

Apr 07, 2026

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1.4742 stainless steel, commonly known as X10CrAlSi24 or UNS S12400, is a high-chromium ferritic heat-resistant stainless steel with exceptional high-temperature oxidation resistance due to its elevated chromium and aluminum content. With 23-26% chromium and 1.20-1.80% aluminum, it offers superior resistance to scaling and oxidation at temperatures up to 1100°C, combined with excellent resistance to sulfidation and carburization. The aluminum addition promotes the formation of a highly stable, adherent aluminum-chromium oxide scale that provides protection even in aggressive high-temperature environments. This makes it an ideal material for demanding applications such as furnace components, heat treatment equipment, and petrochemical processing.

Standard	Equivalent Grade
EN (Europe)	1.4742
ASTM/AISI (USA)	X10CrAlSi24, UNS S12400
Common Name	Chromium-aluminum steel

Element	C	Si	Mn	P	S	Cr	Al
Content (%)	≤ 0.12	0.70 - 1.40	≤ 1.0	≤ 0.04	≤ 0.03	23.0 - 26.0	1.20 - 1.80

Property	Yield Strength (Rp0.2)	Tensile Strength (Rm)	Elongation (A)	Hardness (HB)
Typical Value (Room Temp)	≥ 300 MPa	500 - 700 MPa	≥ 20%	≤ 220
Typical Value (900°C)	~ 35 MPa	~ 55 MPa	~ 40%	-

Superior High-Temperature Oxidation Resistance: The high chromium content (23-26%) combined with elevated aluminum (1.20-1.80%) promotes the formation of a stable, highly adherent aluminum-chromium oxide scale that provides exceptional resistance to scaling and oxidation up to approximately 1100°C (2010°F).

Excellent Sulfidation and Carburization Resistance: Performs exceptionally well in sulfur-containing and carburizing atmospheres where conventional stainless steels rapidly degrade.

Good Thermal Fatigue Resistance: The ferritic structure provides good resistance to thermal cycling, making it suitable for applications with repeated heating and cooling.

Low Thermal Expansion: Lower thermal expansion than austenitic grades, reducing thermal stress in cyclic heating applications.

Furnace Components: Radiant tubes, heating elements, furnace linings, burner parts, and support grids.

Heat Treatment Equipment: Retorts, muffles, baskets, and trays for high-temperature heat treating operations.

Petrochemical Industry: Components in reformers, crackers, and high-temperature process equipment.

Industrial Heating: Recuperators, heat exchangers, and radiant tube sheaths.

Glass Industry: Glass handling equipment and kiln components.

Cement Industry: Preheater cyclones and ducting.

Waste Incineration: Combustion chambers and heat exchangers.

1.4742 offers superior high-temperature oxidation resistance compared to both 1.4762 and 1.4720 due to its elevated aluminum content (1.20-1.80% vs. 0.70-1.20%). The higher aluminum promotes a more stable and protective oxide scale, providing better resistance to scaling at elevated temperatures. While 1.4762 has similar chromium content (23-27%), 1.4742's additional aluminum provides enhanced oxidation resistance, particularly in cyclic heating applications. Compared to 1.4720 (17-19% Cr, 0.70-1.20% Al), 1.4742 offers higher temperature capability (1100°C vs. 950°C) and better resistance to aggressive atmospheres. 1.4742 is the preferred choice for the most demanding high-temperature applications where maximum oxidation resistance is required.

Low heat input welding techniques are essential to minimize grain growth in the heat-affected zone

Preheating (250-350°C) is recommended for thicker sections to reduce thermal shock

Austenitic filler metals (309L, 310L) are recommended for better weld ductility and to avoid embrittlement

Post-weld annealing at 780-820°C followed by slow cooling may be required to restore ductility

The high aluminum content can significantly affect weld pool fluidity and may require special techniques

For critical applications, welding should be performed with qualified procedures

Resistance welding is often preferred for thin gauge applications

1.4742 is suitable for continuous service up to approximately 1100°C (2010°F) and intermittent service up to 1150°C (2100°F). It maintains excellent oxidation resistance within this range, making it suitable for the most demanding furnace components and high-temperature industrial processes. For applications requiring even higher temperature capability (above 1150°C), nickel-based superalloys may be required. The aluminum content provides exceptional protection against scaling at elevated temperatures, but the material has limited creep strength above 1000°C and should not be used for load-bearing applications at these extreme temperatures.

GNEE Steel supplies premium high-temperature 1.4742 (X10CrAlSi24) stainless steel in plate, sheet, bar, and strip forms for the most demanding heat-resistant applications. We provide full material certification (EN 10204 3.1) and processing support including cutting, forming, and welding guidance. If you have any requirements, please feel free to contact us.